The present invention relates generally to the field of conveying and sorting and, more particularly, to a method and apparatus for measuring the center of gravity of a package on a moving conveyor and then pushing said package proximate its center of gravity to divert it from the conveyor without inducing a significant rotation.
Modern parcel delivery services typically rely upon automated sorting systems to quickly and accurately sort packages into defined groups for distribution and delivery. The demand for faster sorting is one of the driving forces behind current innovations in the field of automated parcel sorting. As sorting systems are required to process more and more packages per hour, the devices for conveying, sorting, and diverting packages are becoming more sophisticated.
The demand for high-speed sorting has also sparked a need for sorting systems that are capable of handling a wide variety of packages having different sizes, shapes, and weights. Generally, an automated sorting system that does not require pre-sorting of packages by hand into like-size groups, for example, can proceed to final sort much quicker and with less cost.
High-speed conveying and sorting of large numbers of packages presents a variety of technical challenges, especially when the size, shape, and weight of the packages vary widely. The orderly diverting of packages of different weights, for example, requires a diverter capable of gently exerting a force that is proportional to the measured weight of the package. Similarly, the orderly diverting of packages of different sizes and shapes requires a method and apparatus for determining the optimal pushing location on each package, according to its particular size and shape, and a system to control the motion of the diverter at the appropriate time.
In a high-speed sorting system, it is advantageous to divert objects without causing them to topple, turn, or start spinning. Conveyors and other devices downstream work more efficiently when the entering objects are stable and proceed in an orderly manner. A rotating package can jam downstream devices, interfere with stacking operations, or slide off the side of a conveyor, for example. Delays and system shutdowns caused by a spinning package are expensive and may interfere with sequential processing.
The orderly diverting of selected packages from among a diverse group of sizes and shapes is further complicated by the presence of soft, flexible pouches. The flexible pouch typically has dimensions that are difficult to measure, edges that are difficult to define, and a host of other unique characteristics requiring special handling.
Thus, there remains a need in the art for a method and apparatus to sort and divert packages from a group of packages having widely diverse characteristics.
There is a further need for a method and apparatus to divert packages with improved accuracy.
There is a related need for a method and apparatus to calculate the approximate center of gravity of a package from measured characteristics.
There is also a need for a method and apparatus to sense and transmit data about an object to a controller configured to direct and control the movement of downstream sorting and diverting components.
The present invention overcomes deficiencies in the prior art by providing a method and apparatus for measuring and diverting objects from a moving conveyor based upon various measurements. Stated generally, the invention comprises an array of sensors to measure the object, a signal processor to calculate or assign the approximate center of gravity, a diverter, and an actuator in communication with the signal processor to move the diverter such that it pushes against the approximate center of gravity of the object.
More particularly described, the present invention provides a conveying apparatus for evaluating a plurality of parcels being conveyed thereon, the plurality of parcels having differing lengths, the plurality of parcels including a parcel, the apparatus comprising a first conveyor defining a first conveying surface and including an exit location, a first sensor configured for sensing the presence of a first parcel portion of the parcel while the parcel is on the conveying surface, the first sensor configured to provide a first sensor signal when the first parcel portion moves out of the sensing range of the first sensor due either to tilting of the parcel over the crest, or alternatively due to movement of the parcel along the first conveyor portion without tilting, the first sensor being a first distance from the exit location, a second sensor configured for sensing the presence of a second parcel portion of the parcel while the parcel is on the conveying surface, the second sensor configured to provide a second sensor signal when the second parcel portion moves out of the sensing range of the second sensor due to tilting of the parcel over the crest, or alternatively due either to movement of the parcel along the first conveyor portion without tilting, the second sensor being a second distance from the exit location, the second distance being less than the first distance, and a signal processing device for receiving the first and second signals and for determining for each of the parcels if one of two conditions is met:
1) a first condition in which the first and second sensor signals are generated within a predetermined time;
2) a second condition in which the first and second sensor signals are not generated within the predetermined time, the signal processing device providing a different output regarding parcel length depending on whether the first or second condition is met.
In another aspect of the invention, the inventive system is configured to actuate a diverter at a time when the cleats of the diverter will push against the approximate center of gravity of the object.
Therefore, it is an object of the present invention to provide an improved conveying system which provides improved sorting characteristics.
It is a further object of the present invention to provide an improved conveying method and apparatus which increases sorting capacity.
It is a further object of the present invention to provide an improved conveying method and apparatus, which recognizes differences in, parcel flexibility.
It is a further object of the present invention to provide an improved conveying method and apparatus, which recognizes differences in, parcel size, particularly length.
It is also an objective of the present invention to provide an improved method and apparatus that calculates or approximates the approximate center of gravity of an object based upon the measured characteristics.
It is a further object of the present invention to provide an improved conveying method and apparatus which diminishes rotation of the parcel during ejection of the parcel from the belt.
It is an further object of the present invention to provide an improved conveying and sorting system that diverts selected objects from a group of objects having widely diverse sizes and shapes.
It is further object of the present invention to provide a system for sensing and transmitting data about an object to a controller that is configured to direct and control the movement of downstream sorting and diverting components such that the diverting of various size objects may be accomplished without inducing unwanted rotation.
These and other objectives are accomplished by the method and apparatus disclosed and will become apparent from the following detailed description of a preferred embodiment in conjunction with the accompanying drawings in which like numerals designate like elements.